Tuning-fork



(Model.)

D. W. SBGROVE.

TUNING PGRK.

No. 329,090. Patented Oct. 27, 1885.

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UNITED STATES PATENT OEEICEO DAVID WV. SEGROVE, OF SPRINGFIELD, OHIO.

TUNING-FORK.

SPECIFICATION forming part of Letters Patent No. 329,090, dated October 27, 1885.

Application tiled August Q1, 1885.

To all whom t may concern:

Be it known that I, DAVID W. SEeRovE, a citizen of the United States, residing at Springfield, in the county of Clark and State of Ohio, have invented certain new and useful Improvements in Tuning-Forks, of which the following is a specification.

My invention relates to variable or adjustable tuning-forks; and the objects of my invention are, first, to provide a tuning-fork of ordinary or moderate size whereby sounds of any desired pitch may be produced, and, second, to provide a bridge or cross-bar of novel construction adapted to be readily adj usted to the required position to obtain the desired pitch.

My invention consists in various constructions and combinations of parts, hereinafter described and claimed.

In Ithe accompanying drawings, Figure l is a perspective view of a fork embodying my invention. Fig. 2 is a plan view of the same, showing the handle removed therefrom. Fig. 3 is aperspective View of the bridge or crossbar in detail. Figs. 4 and 5 are views of a modified form of the bridge. Figs. 6 and 7 are views of the fork in different stages of construction, and Figs. 8 and 9 are views illustrating the manner of forming the bridge from one piece of metal.

Like parts are indicated by similar letters of reference throughout the several views.

.In thesaid drawings, A represents the fork proper; B, the adjustable bridge or cross-bar therein, and G t-he handle, which is made separate from the fork, and preferably screwed therein.

The adjustable bridge B is adapted to slide between the prongs a a of the fork, and is held therein by the spring or resilience of the said prongs. The prongs a c are provided with graduations corresponding to the different tones or semi-tones to be produced by the fork. In order that the bridge may be adjusted accurately at the mark or graduation to produce a given tone, and also to hold the bridge from slipping transversely through the fork, I provide the said bridge on either side with projections b b, adapted to extend over the top of the respective prongs, as shown. These pro- Sr-rial No. 157,744. (Model.)

jections serve as guides, ormarkers, whereby the exact graduation desired maybe obtained.

To preserve the bridge at all times at right angles across the fork, and thus prevent the said bridge from being forced out by the elasticity of the prongs c a, pressing on the respective ends thereof, and at the same time to secure accuracy in the tone produced by the fork at a given graduation, I provide the bridge with backwardly-extending guides or projections c, which extend from said bridge in close proximityto the prongs c a. These guides c I make in one piece of metal with the bridge B by first stamping the bridge out as shown in Fig. 8 and then shearing and forcing the projections c outward, as shown in Figs. 3 and 9.

It is obvious that the guides may be formed in different ways--as, for instance, as shown in Figs. 4 and 5, in which case the guides are made inaseparate piece and riveted or otherwise secured to the bridge B.

In order to reduce the length and size of the i fork to an ordinary or moderate size, and at the same time adapt the fork to securearange of an octave in extent, I provide the prongs a a with enlarged or bell-shaped ends e c, the body of the prongs between the said enlarged ends and the base e being made quite slender. The base e is made heavier than the body of the prongs to secure the proper strength.

By making the handle O separate from the fork proper, as above stated, I am enabled to make the fork much more economically than could be done were the handle stamped out in one piece with the fork, as heretofore. In constructing the fork I take a straight bar of steel, as shown in Fig. G, cut to the proper length and of a size suiiicient to form the width of the prongs and the enlarged ends thereof. This bar is then placed in a die and stamped out to the shape shown in Fig. 7, after which it is bent into the form shown in Fig. 2 and the handle inserted therein. The handle is preferably turned up round and knurled on its outer surface, and is screwed or otherwise secured into the base e of the fork proper.

In order to get a perfect bearing between the prongs c c and the bridge B, and thus securea perfect tone in anyposition of adj ustinent which the bridge may occupy, I construct the ends of rco said bridge slightly concave, so that a bearing or Contact is-secured only at the sides of the prongs. This not only secures a perfect contact at all times between said prongs and bridge, but also lessens the friction between said parts, rendering the bridge very easily adjustable, and at the same time holds the bridge more rmly in its position. I have shown the concave ends of the bridge adapted to bear against the inside of the prongs,though it is evident that the concave bearings may be used on4 the outside of the prongs with the same result.

It will be seen that by the construction above described I secure a tnning-forl which may be readily adjusted to produce any tone within the octave, and by constructing the prongs of the shape described I am enabled to secure the adjustment necessary to produce an octave in range without materially increasing the length beyond that of an ordinary non-adjustable or single-tone fork.

Having thus described my invention, I claim- 1. rlhe combination,witha tuning-fork provided with graduations on the prongs thereof, of an adjustable bridge between said prongs, said bridge being provided with projecting ends adapted to mark the position ot' adjustment, substantially as set forth.

2. The combination, with the prongs of a tuning-fork, of a sliding bridge provided with concave ends adapted to form a bearing on each side of said prongs, substantially as set forth.

3. The combination, with the prongs of a tuning-fork, of a sliding bridge between said prongs and baekwardly-projeeting guides on said bridge, substantially as and for the purpose set forth.

4. The combination, with the prongs of a tuning-fork, of a sliding bridge therein provided with backwardly projecting guides formed in one piece therewith, substantially as specified.

5. rIhe combination, in a tuningiork, with the adjustable sliding bridge, of the forkprongs provided with the enlarged or bellshaped ends, substantially as and for the purpose set forth.

6. rlhe combination, with a tuning-fork, of a removable handle adapted to be secured to the base of said fork, substantially as specified.

7 The combinatioinwith the fork the prongs of which are formed with enlarged or bellshaped ends, of an adjustable bridge with eoncave ends and backwardly-projecting guides, substantially as set forth.

8. rIhe combination, with a fork having graduated prongs, said prongs being provided with enlarged or bell-shaped ends, ot' an adjustable bridge provided with end projections adapted to extend over the said graduations and mark the position of said bridge, substantially as specified.

9. Ihe combinatio1i,with a fork with prongs having enlarged or bell-shaped ends and enlarged base, of a separate or removable handle adapted to be secured in said base and an adjustable bridge in said prongs, substantially as set forth.

In testimony whereof I have hereunto set my hand this 2d day of March, A. D. 1885.

DAVID W. SEG-ROVE.

Vitnesses :v

Crmsn STEWART, PAUL A. STALEY. 

